In reality, it is better not to depend on impromptu discussions (meaning not grabbing people to discuss something with as soon as an idea hits you). When a person comes up with an idea and wants to discuss, you are almost always better off notifying people you want to get together with and set up a time. This will have the added advantage of not disturbing the flow of the other person, as well as give you sometime to re-iterate over exactly what you want to discuss. In that case, a remote worker will most likely be factored in.

Also, I was talking about the case where ALL employees in IT are remote and not just some of them. In that model, you all adjust to working in a virtual environment, highlighting actions that maximize interaction and minimizing those that dont.